Active steering systems are known from the related art, in which an additional steering angle is impressed upon the driver's steering angle, using an electric motor and a planetary gear. This system may be used to control the steering transmission depending on the situation and to undertake driving stabilization interventions via the control of the wheels. This active steering is also used as power steering, in order to set a boosting of the steering motion as a function of speed. Furthermore, various systems are known for monitoring tire air pressure. These are able to work directly with a pressure sensor in the tire or be based on an evaluation of the rotational speed of the wheels. In this context, air pressure that is too low is indicated to the driver using a warning light.